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Backgrounder on License Application for Depleted Uranium at U.S. Army Sites

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The Nuclear Regulatory Commission issued a license to the U.S. Army in October 2013 to possess and manage depleted uranium (DU) at two Army training sites in Hawaii. The license applies to the Schofield Barracks on Oahu and Pohakuloa Training Area on the big island of Hawaii. It covers DU from the spotting rounds used with the Davy Crockett weapons system in the 1960s. Used to assist with targeting accuracy, the spotting rounds emitted white smoke on impact but did not explode. This system was previously classified and records of its use were closely guarded. The Army eventually plans to amend the license to add other U.S. sites where soldiers trained with Davy Crockett weapons.


Natural uranium is made up of three isotopes: U-234, U-235 and U-238. "Depleted" uranium has a lower percentage of U-234 and U-235 than natural uranium and is less radioactive. DU is about twice as dense as lead, making it useful in commercial and military applications. It can be toxic to the kidneys if ingested in large amounts, such as by inhaling dust or drinking contaminated water.

A number of Army sites across the U.S. have DU fragments from spotting rounds left from training with the Davy Crockett system from 1960-1968. The Atomic Energy Commission, the NRC's predecessor, gave the Army a license to make and distribute the spotting rounds. Under the earlier license, the Army distributed spotting rounds to a number of Army installations for training. Each round contained about six ounces of DU. That license expired in 1978, after the Army had stopped producing and distributing the spotting rounds.

In 2005, the Army found tail assemblies from the spotting rounds at the Schofield Barracks on Oahu. That discovery prompted a review of all sites where the Army trained with the system. The Army found DU at other sites, including the Pohakuloa Training Area on the big island of Hawaii. The Army has enough DU at these sites that, under NRC regulations, it must have a possession license. The Army applied for an NRC license in November 2008.

An Army information booklet states that the DU is mostly in large fragments. It is on operational ranges not accessible to the public. Data the Army collected and analyzed show there is no immediate health risk to people who work at the ranges, live nearby or travel near the site. The high density and large fragment size mean the DU cannot easily become airborne or move off-site.

The Nuclear Regulatory Commission's Role

Part of the NRC's role as a regulatory agency is to oversee licensed "source material," a category that includes DU. The NRC license allows the Army to possess up to 275 pounds of DU at the two Hawaiian installations. Now that the Army has an NRC license, it will be required to comply with NRC regulations and standards for protecting the public and the environment from exposure to radiation and is subject to NRC inspections and periodic reviews.

The license requires the Army to implement a radiation safety plan and a physical security plan. It also requires the Army to provide an air and plant sampling plan for NRC review within 90 days. The NRC must review sampling results before deciding whether to lift restrictions on activities that could disturb the DU. These requirements of the license are meant to ensure the DU will not pose a future health risk. The license does not authorize the Army to use the DU or decommission the sites without additional review and approval by the NRC.

The initial license covers only the DU at the Hawaiian sites. In the future, the Army will be required to amend the license to address DU at the other sites. These sites can only be added to the license after the Army has studied them and developed site-specific environmental radiation monitoring plans. The additional sites include Forts Benning and Gordon (Georgia); Forts Campbell and Knox (Kentucky); Fort Carson (Colorado); Fort Hood (Texas); Fort Lewis, currently called Joint Base Lewis-McChord, and the Yakima Training Center (Washington); Fort Bragg (North Carolina); Fort Polk (Louisiana); Fort Sill (Oklahoma); Fort Jackson (South Carolina); Fort Hunter Liggett (California); Fort Greeley (Alaska); Fort Dix (New Jersey); and Fort Riley (Kansas).

For additional information, see the Army's website on depleted uranium in Hawaii.

M101 Spotting Round (Source: U.S. Army)[2].
M101 Spotting Round (Source: U.S. Army).

October 2013

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